A within-subjects design was employed, with each subject performing the task in all
conditions (in counterbalanced order). Participants were first introduced to the simulator
and to the task. The three modalities of directional information were demonstrated:
audio, tactile and combined audio+tactile). They were then given six minutes to drive
the simulator in order to get used to it with signs on the road giving left-right
instructions.
Each condition then lasted six minutes, during which subjects received 18 instructions
(nine left and nine right) in random order. The time between instructions was
randomly between 15 and 24 seconds. Subjects were instructed to drive in the middle
lane and to switch to the left or right lane according to the signal and to come back to
the middle lane immediately after having reached the respective lane. At the end,
participants were given a questionnaire and asked to rate the conditions according to
their preferences (e.g. being annoying or pleasant). Further open-text explanations
(e.g. why it was annoying) for their statements were collected, as well as demographic
data.